Abstract: The invention relates to a tensioning device (01) for tensioning a coil spring (02) that is supported on a main shaft (03) and at a fixed end is rotatably fixedly connected to a frame. The tensioning device (01) includes a gear drive (05), having a first gear element (06) that is axially displaceably guided on the main shaft (03) and rotatably fixedly connected to a free end of the coil spring (02), and having a second gear element (07) that is in drive engagement with the first gear element (06) in order to set the first gear element (06) in rotation about the main shaft (03). The tensioning device (01) also includes a retaining element (19) that holds the second gear element (11) in the position of drive engagement with the first gear element (06). Furthermore, the tensioning device (01) includes a drive element that is coupled to the second gear element (12) in order to set it in rotation.

Abstract: A retractable warping winch with a supporting housing, adapted to be stably fixed to a deck of a vessel at an opening thereof, and a bell, including a base and a drum integral to each other. The bell is movably supported by the housing so that it can vertically shift therein between an extracted working position and a retracted rest position. The winch also includes a driving mechanism to rotate the bell, including a motor and a transmission. The driving mechanism includes a drive hub mounted in the housing. The base of the bell is mounted in the drive hub to be rotatably integral therewith and free to axially shift with respect thereto. The drive hub is mounted in the housing to be rotatably free and axially constrained thereto. The motor is mounted on the housing, externally and laterally thereto.

Abstract: A measurement assemblage for measuring the torque on a shaft, and in particular the torsional moment of the shaft, having a sensor device that is configured to measure a magnetic field carried or generated by the shaft; a sensor holder for holding the sensor device and for disposing the sensor device with respect to a region of an outer circumferential surface of the shaft; and at least one force element that is configured to dispose the sensor holder, by force impingement, in stationary fashion with respect to the region of the outer circumferential surface of the shaft, the at least one force element being configured to exert a tensile force on the sensor holder in such a way that the sensor holder is pulled against the region of the outer circumferential surface of the shaft as a result of the tensile force.

Abstract: A winch controller for a hoisting apparatus for a wireline operation operates as a closed loop controller. The winch controller is adapted to control a winch or, if included, a winch and a capstan in a coordinated manner. The winch controller may utilize process variables including the tension of the cable between the winch and the capstan. The controller is coupled to a power pack adapted to power the winch and capstan. The power pack and controller are configured such that the capstan may be selectively removed from the system when it is not needed.

Abstract: The invention is a portable powered rope climbing device, which can carry persons and objects to ascend or descend along a climbing rope, and ensure controllable speed. The invention comprises a battery pack, an electromagnetic brake direct current motor, and an output shaft of the motor connected with an input shaft of a reducer. An output shaft of the reducer and the input shaft of the reducer are arranged in a 90-degree manner. A driving rope pulley is fixed to the output shaft of the reducer. A climbing rope is wound inside the driving rope pulley. A warping brake rope-pressing pulley block and rope-pressing pulleys tightly press the climbing rope. The climbing rope is wound between the driving rope pulley and a reversing rope pulley and is led out of the driving rope pulley. A speed control module is connected with the motor.

Abstract: A friction grip hoist (1) includes: at least one body (2); a pulley (3) mounted on the body, the pulley including a pin (4) and a wheel (5) having an outer peripheral groove (6) for receiving a cable; drive elements (7) for driving rotation of the wheel; and holder elements (15) for holding the cable inside the groove (6) of the wheel. The pin, referred to as a “dynamometer” pin, about which the wheel of the pulley is mounted to rotate is fitted with measurement elements (11) for measuring at least one magnitude representative of at least radial forces or loads exerted on the pin, and the hoist includes a monitor unit fitted with processor elements and with elements for issuing an alert signal and/or for controlling the elements (7) for driving rotation of the wheel of the pulley as a function of the at least one measured magnitude.

Abstract: A safety brake device for a theatre hoist to prevent the uncontrolled release of a load that is suspended above or below people includes an overrunning clutch and a torque disc. The torque disc only rotates with the overrunning clutch when the load is lowered, but must overcome friction forces applied to the surface of the torque disc to do so. The friction forces are constantly applied to the torque disc by maintaining friction material in contact with the torque disc. The friction material is a non-asbestos, non-metallic composite saturated with a lubricant.

Abstract: An auto-arresting safety device, comprising a housing; a fall arrest system supported by the housing, and having a first component moveable with respect to a second component, the fall arrest system being actuatable in response to a load to arrest movement of the first component relative to the second component, the fall arrest system being resettable to restore movement of the first component relative to the second component upon the load being at least partially removed; and a disabling system operable to prevent resetting of the fall arrest system upon the load exceeding a threshold load, such that, when actuated, the disabling system renders the safety device inoperable.

Abstract: The present invention relates to control means (20) for controlling a lifter device (10), the control means having a grip (25) comprising a body (30) extending longitudinally in a first direction (D1) in elevation from a first end (31) to a second end (32), said control means (20) including at least one control member (40) for controlling said lifter device (10). The body (30) includes a groove (33) extending longitudinally in a second direction (D2) in elevation, said groove (33) having a back wall (34) and an open section (35) that is open to the outside (EXT) of the grip (25) so that a suspension member (15) can be reversibly inserted in said groove (33) through said open section (35), the suspension member (15) being held in said groove (33) by the hand of an operator.

Abstract: A constant pulling force winch control system includes a sensor that senses a degree of winding of a winch cable around a winch drum, and a control system configured to control a winch motor to achieve a constant pulling force on the winch cable based on the degree of winding sensed by the sensor. The sensor may be a position sensor that measures a position of the winch cable relative to a centerline of the winch drum as the degree of winding. The position sensor may sense an angular position of a tension plate relative to a tensioner shaft to measure the degree of winding. The winch motor may be a hydraulic winch motor or an electric motor, and the control system is configured to control the power applied to the hydraulic winch motor to achieve the constant pulling force based on the degree of winding sensed by the sensor.

Abstract: A friction grip hoist (1) includes: at least one body (2); a pulley (3) mounted on the body, the pulley including a pin (4) and a wheel (5) having an outer peripheral groove (6) for receiving a cable; drive elements (7) for driving rotation of the wheel; and holder elements (15) for holding the cable inside the groove (6) of the wheel. The pin, referred to as a “dynamometer” pin, about which the wheel of the pulley is mounted to rotate is fitted with measurement elements (11) for measuring at least one magnitude representative of at least radial forces or loads exerted on the pin, and the hoist includes a monitor unit fitted with processor elements and with elements for issuing an alert signal and/or for controlling the elements (7) for driving rotation of the wheel of the pulley as a function of the at least one measured magnitude.

Abstract: The invention relates to a subsea marine load raising and lowering system (1) for use on a vessel, preferably a vessel for laying an offshore pipeline, which system comprises first and second winches (2, 6) for raising or lowering first and second cable portions (4, 8) connected via an equalizing sheave (11), to the axle (12) of which a load connector (13) is connected. The system comprises operating means to perform synchronous raising or lowering of the cable portions. The system further comprises overload protection systems provided at both winches, and a safety assembly (15) preventing any substantial further movement of the cable portions (4, 8) in case the cable portions do not operate synchronously, comprising a structure (15a) mounted to the axle (12) of the equalizing sheave (11) having passages (15c) for the cable portions and further comprising stops (15b) arranged on each cable portion above and in the vicinity of the structure (15a).

Abstract: A power assist device includes: holder holding a workpiece; a pair of wires each having one end connected to the holder to suspend the holder; a pair of wind-up wheels winding up respective other ends of the wires; a pair of motors rotationally driving the respective wind-up wheels; a pair of rotation detectors detecting rotation information of the respective motors; a pair of torque detectors detecting drive torque in the respective motors; and controller controlling drive of the motors. The controller calculates operating force to the workpiece based on the rotation information detected by the rotation detectors and the drive torque of the motors detected by the torque detectors, and controls the motors to assist the operating force that is calculated, to move up and down the holder.

Abstract: An electrically driven mooring winch is provided. The mooring winch includes a winding drum, an AC motor configured to drive the winding drum, a frequency conversion unit connected to the AC motor, and a control unit configured to control the frequency conversion unit on the basis of an indicator for tension of the mooring rope. The control unit is configured to set a reference value of rotational speed of the AC motor to a predetermined value, drive the AC motor in one direction for a predetermined time interval, define a first value of a torque of the AC motor, drive the AC motor in an opposite direction for the predetermined interval, define a second value of the torque of the AC motor, and compute a torque estimate using the first and second values of the torque.

Abstract: A method for lift compensation of an item (12) which is connected to a vessel (1) by means of a rope (4) which is coiled around the rope drum (6) of a lifting device (2), the lifting device (2) being provided with a heave compensator (20), a controller (30) of the heave compensator (20) controlling the effect of the driving device (32, 34, 42) of the rope drum (6) on the basis of a heave term and a deviation term, the method comprising: —bringing a correction term into the heave compensation when, because of environmental forces, the force on the rope (4) falls outside a first limit (d, e); and—leaving the correction term out when the force on the rope (4) is within a second limit (c, f), the second limit (c, f) being equal to or different from the first limit (d, e).

Abstract: A hoisting device or crane can be operated with at least two different maximum loads. The maximum load that can be hoisted in each case is correlated with the hoisting speed in order to prevent the dynamically developed peak load from exceeding the predetermined allowed load limiting values of the components of the crane or the hoisting device.

Abstract: A drilling rig control system adapted for easy interface between a compressed air supply and a drilling rig clutch and brake. Both manual and automatic controls are provided to initiate the device to interrupt and vent the compressed air supply to the clutch and concurrently communicate compressed air to the brake to cause it to engage the drum winding the cable for the rig. Over-pull sensors monitor cable tension and initiate valves in the control system to initiate the compressed air interruption and rerouting upon any sense of over-pull.

Abstract: A multi-staged hinge assembly and a portable electrical device comprising the multi-staged hinge assembly are provided. The multi-staged hinge assembly utilizes a non-circular spindle to associate with a plurality of movable elements disposed thereon. One of the body portions of the portable electrical device automatically tilts at an angle after the body portion slides by the multi-staged hinge assembly. The user could further adjust the angle to meet the demands of various situations.

Abstract: To provide a winding mechanism and a trawling apparatus capable of eliminating an excessive tension or slack generated in a wire wound around a drum and keeping the tension or wire length of the wire constant. A winding mechanism with tension control function includes a reversibly rotatable liquid-pressure motor rotating a drum having a wire wound therearound, a liquid-pressure pump coupled directly with the liquid-pressure motor and supplying hydraulic oil, and an electric motor rotating to drive the liquid-pressure pump. The winding mechanism further includes a control unit controlling a torque of the electric motor based on a variation in load current of the electric motor and winding off or winding up the wire to keep the tension of the wire at a set value.

Abstract: A portable pulling tool is provided including an integrally formed one-piece gear case for positioning all of the gear train components. The gear train includes a combination of helical gears and a differential planetary gear unit in a unique configuration. A motor control system is provided to automatically shut off the motor when a predetermined current load is detected. A multi-segment LED is provided to indicate to the user the amount of load that is being applied.

Abstract: A device for a wave-power plant includes a self-tightening winch with a winch wire. The winch wire is connected to a wave-power-operated absorption element at one end and to a cable drum of the self-tightening winch at the other end. The cable drum is connected via a transmission system to an outgoing axle which is further connected to an energy-storing restructuring machinery. Movement of the absorption element results in rotation of the cable drum and transmission of mechanical energy from the cable drum to the rotating outgoing axle and to the restructuring machinery. The transmission system includes a slip clutch connected to the outgoing axle, which protects the components in the wave-power plant, particularly the components in the restructuring machinery, against overload in the event of large wave amplitude.

Abstract: A rope winch has at least one bearing support and a rope drum supported on the at least one bearing support so as to be rotatable about a drive axis. A drive motor and a gear connected to the drive motor are provided, wherein the drive motor drives the rope drum about the drive axis through the gear. At least one sensor that senses a load acting on the rope drum is provided. An exchangeably secured component that is exchangeable without dismounting the at least one bearing support is provided. The at least one sensor is arranged on the exchangeably secured component.

Abstract: A method for controlling the tension in a spooled device disposed on a winch, comprises providing an input signal to a controller indicative of a measured tension in the spooled device, providing an input signal to the controller indicative of a desired tension in the spooled device, and providing an output signal from the controller to adjust the speed of the winch based on a difference between the desired tension in the spooled device and the measured tension in the spooled device.

Abstract: A safety device for a fall arrest system comprises: a body, attachment means for attaching the safety device to a support structure, a drum mounted for rotation relative to the body, a safety line wound on the drum, a speed sensitive clutch connected to the drum, and a linear energy absorber connecting the body to the attachment means, in which the speed sensitive clutch is adapted to respond to rotation of the drum relative to the body in a direction tending to unwind the safety line from the drum and above a predetermined speed by locking the drum against further rotation in said direction relative to the body, and the linear energy absorber is adapted to respond, when the speed sensitive clutch has locked the drum, to an applied load along the safety line greater than a threshold value by deploying and absorbing energy so that the attachment means moves away from the body.

Abstract: A powered rope ascender that supports a person or a load while ascending a vertical rope. The rope ascender has a motor driven capstan drum that engages the rope. A pinch roller grips the rope against the capstan drum. A load limiting assembly releases the grip by the pinch roller when the load supported by the ascender exceeds a predetermined amount. A centrifugal clutch reduces starting torque required by the motor and the outer drum of the centrifugal clutch interacts with a brake to hold position on the rope. For heavy loads a motion activated brake is used. Hand controls provide a freewheeling, a braking and an ascending mode of operation. A harmonic drive or planetary reduction gears provide speed reduction from the motor to the capstan drum. The powered rope ascender can be threaded on the rope without access to a rope end.

Abstract: Speed limiter system to detect over speed and generate a signal to cut the power and if necessary operate brakes. It consist of the limiter itself, with a tension pulley. The limiter consists of weights connected by a mechanism that moves asymmetrically and by centrifugal force when an over speed occurs to operate the lever of an electrical contact, with the possibility of remote resetting using the necessary means. On the other hand, the tension pulley provides sufficient tension to both sections of the cable via an adjustable compression spring or by means of weights suspended on an articulated arm, both transmitting sufficient tension to the tension pulley axle.

Abstract: A hoisting device, especially a cable or chain block, with a hoisting transmission having at least one shaft and with a hoisting load measuring mechanism. In order to determine the hoisting load as accurately as possible and possibly independent of the reeving and without additional structural height, the hoisting load has at least one sensor for detecting the deformation of the shaft produced by the hoisting load and the detected deformation is used as a quantity in determining the hoisting load.

Abstract: The present invention provides an automatic system for engaging the hydromatic brake on a drilling rig or a service rig. This system monitors both the hook load and traveling block velocity, and uses an electrical solenoid to activates the hydromatic when either the hook load or rotating drum velocity exceeds a maximum value, requiring hydromatic brake engagement.

Abstract: Disclosed herein is a system designed to manage or slow the block travel speed down to safe speeds when the rig is operating in a light load/high speed condition. The system monitors and controls engine torque and horsepower, providing the minimum amount of each necessary to pull the light load out of the hold without providing sufficient excess torque to pull the load through a snag.

Abstract: An improved chain motor drive controller is provided for a chain hoist. The system employs a position encoder including a position sensor located within the casing of the chain hoist to producing encoded electrical position signals. A motor pulley is mounted on the chain motor rotary drive shaft and is coupled by a cogged belt to rotate an encoder pulley that is mounted on the same shaft as the position sensor. A mechanical coupling is thereby provided entirely within the casing of the chain hoist to transmit rotary motion from the rotary drive shaft directly to the position sensor. Also, tracking circuitry, likewise located entirely within the chain hoist casing, receives electrically encoded destination signals and compares these to signals from the position sensor.

Abstract: A human power amplifier includes an end-effector that is grasped by a human operator and applied to a load. The end-effector is suspended, via a line, from a take-up pulley, winch, or drum that is driven by an actuator to lift or lower the load. The end-effector includes a force sensor that measures the vertical force imposed on the end-effector by the operator and delivers a signal to a controller. The controller and actuator are structured in such a way that a predetermined percentage of the force necessary to lift or lower the load is applied by the actuator, with the remaining force being supplied by the operator. The load thus feels lighter to the operator, but the operator does not lose the sense of lifting against both the gravitation and inertial forces originating in the load.

Abstract: A winching arrangement is disclosed for winching a cable comprising a winching frame; a capstan (11) for winding the cable onto; a drive motor (3) for driving the capstan; and a first clutch mechanism for disengaging the capstan from the clutch when the torsional load on the cable exceeds a first predetermined limit. Preferably, the first clutch mechanism (6) is located within the capstan and ideally the clutch mechanism is an adjustable cone clutch mechanism. The winching arrangement can further include a second adjustable clutch mechanism located adjacent the motor for providing secondary disengagement of the motor from the capstan when the cable exceeds a second predetermined limit. Further, a gear reducer (8) can be interconnected between the capstan and the drive motor. Preferably, the arrangement also includes a fixing arm (15, 18) for fixing the winch to an object wherein the cable, the capstan and the fixing arm are aligned substantially concentrically during operation.

Abstract: A device for setting and automatic adjustment of the tractive forces of the cable of an overhead winch for a ski slope preparation and maintenance machine comprising an adjustment control unit connected to a controllable winch drive and a processing device connected to sensors and to the adjustment control unit is described.

Abstract: A boom hoist system for supporting and adjusting the position of a lifting crane gantry is provided including a drum, a drive system, and first and second braking systems for selectively stopping rotation of the drum. The boom hoist system operates independently from crane mechanical works and the first and second braking systems may include sensors for automatically engaging when specified conditions occur in order to prevent a hoisted gantry from falling uncontrollably in the event of a hoist system malfunction or failure.

Abstract: A pneumatic human power amplifier module is usable in conjunction with a wide variety of pneumatic actuators and lifting devices to provide a human power amplifier for lifting a load. The module includes an end-effector, an electronic controller and a pneumatic circuit. The end-effector contains a human interface subsection which is grasped by a human operator and a load interface subsection which engages the load to be lifted. A force sensor in the end-effector detects the force imposed by the operator on the end-effector and transmits a signal representing the magnitude of the force to the controller. The controller in turn sends a command to the pneumatic circuit, which controls the flow of air into the associated pneumatic actuator. The actuator drives the lifting device.

Abstract: A method of stopping of a winding machine that hoists and lowers an object prevents abrasion of the electromagnetic brake and the descent of load. The winding machine, which winches a load up or down in response to a torque command T.sub.REF to the electric motor M produced by the speed controller ASR in accordance with the a speed command N.sub.REF generated by the speed command generation circuit NRC, operates at the stopping of the machine to cease the motor control if the motor speed N.sub.FB is zero after the torque command to the motor M is brought to zero for a predetermined length of time following the issuance of a brake command to the electromagnetic brake which is coupled directly to the motor M.

Abstract: An air lifting and balancing unit including a cylinder, a piston in the cylinder, a ball screw affixed to the piston, a ball nut mounted for rotation on the ball screw, a drum mounted on the ball nut, a chain driven by the drum, and centrifugally actuated brakes mounted on the drum for stopping rotation of the drum when the drum exceeds a predetermined acceleration either due to a loss of load or to a loss of air pressure applied to the piston, and a pneumatic circuit in communication with the cylinder for providing air pressure thereto which applies a force on the piston which is at a substantially constant incremental value in opposition to the force exerted by the load applied to the piston through the chain and the drum and the ball screw regardless of variations in said air pressure to thereby cause the speed of the chain to remain substantially constant.

Abstract: An electric hoist comprising an electric motor and a sheave driven by the electric motor via a reduction gear. The reduction gear comprises a pair of helical gears meshing with each other. One of the helical gears is axially movably arranged on a shaft and is moved in the axial direction thereof when there is a load on the load chain supported by the sheave, and when the axial movement of the movable helical gear is detected by a sensor, the speed of rotation of the electric motor is automatically changed from a higher speed to a lower speed.

Abstract: A winder for winding and unwinding of materials, which utilizes a ball variator and planetary speed reducer in combination with a mechanism functioning as a regulator of speed output and tension desired for the materials. During a winding operation, the growing winding diameter of the material causes a rise in torque at the winding shaft and through a series of planet pinions, an increase of thrust at the ring gear of the planetary speed reducer. This increase of thrust is followed by rotation of the ring gear and control cam via a control lever. The rotation is transmitted from the control cam, through a clutch mounted on the control shaft and a series of gears to an iris plate of the ball variator and through the control shaft to a weight lever. The rotation of the iris plate causes a tilt of the balls of the variator, determining the drive ratio and output speed variation. The rotation of the weight lever causes tension desired for the material.

Abstract: A motor-driven cylinder for lifting apparatus has screw means including intermeshed internally and externally threaded screw means by which a load can be moved upwardly and downwardly by the torque of a motor, the motor-driven cylinder including torque transmission means movable in a first direction and a second direction opposite thereto for transmitting the torque of the motor to the screw means. During operation, the torque transmission means is moved in the first direction by the applied torque of the motor causing compression of a spring. When no torque is produced from the motor due to its malfunctioning or due to a lack of electrical power applied to the motor the torque transmission means is moved in the second direction under the restoring force of the compressed spring into a mechanically braked condition. Thus, a compact, integral, low-cost safety device is provided for preventing the lifting apparatus from falling, accidentally, under the force of gravity.

Abstract: A hoist having a worm safety device in which the worm is continuously meshed with a worm wheel coupled to the drum. The worm is accelerated to a speed greater than that of the worm wheel and at a torque sufficient to overcome the frictional contact between the worm and worm wheel when the hoist direction is reversed.

Abstract: A method for maintaining a substantially constant tension on a towed seismic cable, wherein the instantaneous towing force and the instantaneous cable displacement relative to a fixed shipboard reference are continously measured and sampled. A microprocessor associated with a servo controlled capstan device, uses those measurements to pay out cable or to retrieve cable in response to an increase or decrease in the instantaneous towing force. The microprocessor also tries to minimize the average cable displacement.

Abstract: A system for maintaining a substantially constant tension on a towed seismic cable, wherein the instantaneous towing force and the instantaneous cable displacement relative to a fixed shipboard reference are continuously measured and sampled. A microprocessor associated with a servo controlled capstan device, uses those measurements to pay out cable or to retrieve cable in response to an increase or decrease in the instantaneous towing force. The microprocessor also tries to minimize the average cable displacement.

Abstract: The safety system in a hoist having a motor with a motor shaft, a gear reduction unit, a drum, a safety brake drivingly coupled on an operating element on or close to the drum in which a mechanical out-of-sync detector produces a unidirectional brake-setting output from inputs from the drum and the motor shaft, the unidirectional brake-setting rotational output for setting the brake. In a preferred embodiment, an error correction is made into the detector for obtaining a first unidirectional output during normal operation, and the brake-setting unidirectional rotation is in the opposite direction for setting the brake. One form of detector is a mechanical differential assembly and another form of detector is a set of coaxial shafts that measure differential rotation between the drum and motor input shafts. A unique brake actuator is provided and is easily reset remotely after the brake has been set.

Abstract: A rotary drum cable winding apparatus particularly adapted for constant tension pulling operations in conjunction with stringing aerial electrical cables includes a hydraulic drive and control system utilizing a variable displacement, variable torque hydraulic motor supplied by a pressure compensated hydraulic pump. The motor has a built-in displacement control which is responsive to a predetermined pressure set point which may be varied by a pilot control pressure signal to increase motor displacement per revolution and output torque for a given motive fluid supply pressure. The increasing torque requirements and the reduced rotative speed of the rotary drum coincide with the requirement for relatively constant tension and constant speed of the messenger line or cable being wound on the drum.

Abstract: A hoist having a motor, gear reduction unit, drum, and an emergency brake on the drum or on a drive-coupled element close to the drum. A brake-actuating mechanism is operated in response to a mechanical out-of-sync detector with mechanical inputs directly from the motor shaft and drum shaft or a shaft coupled to the drum. The detector has an output shaft which signals to actuate the brake actuator when there is a variation in the relative angular velocities between the two input shafts to the detector to set the brake. In one embodiment, the output shaft rotation provided from the variation in the relative velocities of the input shafts also provides the force for applying the emergency brake. In another embodiment, the brake is set by a large force spring which is controlled by a trigger mechanism. In still other embodiments, the mechanical detector is driven by an overspeed or speed-sensitive clutch, and/or by an electrically operated clutch.

Abstract: In a device for preventing overload of a vehicle winch, including a line drum, a motor and a planetary gearing between the line drum and the motor, there is a sensor comprising a planet carrier of the planetary gearing. When the winch is overloaded the planet carrier is rotated to a limited extent against the action of a spring force to actuate a switch forming part of the device which interrupts further operation of the winch.

Abstract: Method of controlling two separately operable hydraulic circuits involving monitoring the pressure conditions in one of the circuits, comparing this pressure with a reference pressure which is established in the control system to produce a first error signal which is used to correct if necessary the pressure within the one circuit. Performing the same operation in the case of the second circuit using the same reference pressure. In particular the system and apparatus of the invention is used for controlling the tensions in the warps of a trawl automatically throughout the shooting, trawling and hauling-in of a trawl.

Abstract: The drive motor is pivotally supported axially within the frame so that it rotates slightly if the torque of the motor increases due to the scraper assembly being impeded by animals, equipment, broken slats or the like. This actuates a reversing switch thus reversing the movement of the scraper assembly. If desired, an electric shock circuit can be included which is actuated first, in case the obstruction is an animal. If the animal moves away from the scraper then the scraper proceeds as the reversing switch has not been actuated at this time.

Abstract: A method of stopping of a winding machine that hoists and lowers an object prevents abrasion of the electromagnetic brake and the descent of load. The winding machine, which winches a load up or down in response to a torque command TREF to the electric motor M produced by the speed controller ASR in accordance with the a speed command NREF generated by the speed command generation circuit NRC, operates at the stopping of the machine to cease the motor control if the motor speed NFB is zero after the torque command to the motor M is brought to zero for a predetermined length of time following the issuance of a brake command to the electromagnetic brake which is coupled directly to the motor M.